This invention relates generally to coated articles and in particular, to an article that is coated using an ion plating process and has a color tone similar to the color tone of stainless steel.
About 90% of coated ornamental articles such as watches are gold or silver in color. Stainless steel material is often used to make ornamental articles and is processed by abrasion to provide a color tone similar to that of silver.
However, stainless steel materials generally have a low Vickers hardness, specifically between about 180 and 200 Hv. As a result, the material becomes marred or scratched within a short period of time and the initial ornamental appearance is not maintained. Brass and nickel-silver can also be used to form coated articles and these materials are generally prime-coated with copper or nickel plating. The prime-coating is covered with a palladium alloy, rhodium, silver and the like to obtain silver colored coated articles. However, all of these materials have poor corrosion resistance.
When brass material is coated with a palladium alloy, rhodium, silver or the like by a wet plating process the plated material is only a few microns thick. This is disadvantageous because the coating readily wears away or is damaged through use and the ornamental appearance deteriorates. Additionally, palladium alloys, rhodium, silver and the like are expensive and a low cost ornamental coated article can not be provided.
Accordingly, it is desirable to provide a coating on an ornamental article which has a high degree of hardness and good wearing and mar proof properties and overcomes the shortcoming of the prior art.